1. Field of the Invention
The present invention relates to an ink-jet recording apparatus and an ink cartridge. In particular, the invention relates to an ink-jet recording apparatus capable of judging the residual ink amount reliably and outputting an ink empty signal in a state that the residual ink amount is very small and an ink cartridge used in that ink-jet recording apparatus.
2. Description of the Related Art
As disclosed in Japanese Patent No. 3,075,286, an ink-jet recording apparatus is known which judges a residual ink amount of an ink accommodation unit (i.e., ink cartridge). In this ink-jet recording apparatus, two electrodes are provided in the ink cartridge and electrical resistance between the two electrodes is detected. The detected electrical resistance is always compared with a preset value. The ink-jet recording apparatus outputs a warning signal (near-empty signal) if the electrical resistance is higher than the preset value. At the same time as the output of the near-empty signal, the ink-jet recording apparatus outputs, to a number-of-recorded-sheets counting circuit (number-of-sheets counter), an instruction to start counting of the number of recorded sheets. When the count has reached the number of recordable sheets that corresponds to an ink residual amount at the time of the near-empty detection, the ink-jet recording apparatus outputs an alarm signal (ink empty signal) and stops the recording operation.